20-Hydroxyecdysone primary response gene LmBlimp-1 controls locust molt and survival by regulating chitin metabolism

The Cys2-His2-type zinc finger transcription factor Blimp-1 plays a crucial role in animal development; however, its function in insect molting remains poorly understood. In this study, we investigated the role of LmBlimp-1 in the molting development of the migratory locust Locusta migratoria.

RNA interference (RNAi)-mediated silencing of LmBlimp-1 resulted in severe molting defects, developmental delay and ultimately 100% mortality. Furthermore, knockdown of LmBlimp-1 significantly downregulated the expression of chitinase genes (LmCht5-1, LmCht5-2 and LmCht10) and chitin synthesis-related genes (LmGfat, LmUAP1 and LmCHS1), leading to impaired degradation of the old cuticle and defective synthesis of the new cuticle. Mechanistic analyses further revealed that 20-hydroxyecdysone (20E) induced the expression of LmBlimp-1, indicating that it functions as a primary response gene in the 20E signaling pathway. Knockdown of LmBlimp-1 disrupted the expression of key 20E-response genes, including LmE74, LmHR3 and LmHR4. Moreover, the 20E rescue experiment partially alleviated the lethal phenotype caused by LmBlimp-1 RNAi.

These results demonstrate that LmBlimp-1 acts as a critical regulator that integrates the 20E signal to modulate chitin metabolism and ensure successful molting. Our findings provide new insights into the molecular regulatory network underlying insect molting and offer a theoretical basis for the development of RNAi-based pest management strategies. © 2026 Society of Chemical Industry.